Door stops for maintaining doors in an open position have existed for some time. Door stops have many applications. Fire fighters often use them to prop open doors while fighting fires to make sure that equipment (e.g., hoses) and people are able to move from room to room without hindrance.
Door stops can also be used for security purposes. People tend to be less likely to engage in illicit conduct if they know that their conduct is not entirely private. Based on this principle, propping doors open with door stops can enhance security in some circumstances. For example, hotel maids are often instructed to prop doors open while cleaning hotel rooms in order to guard against the possibility of a person following them into a room, closing the door, and attacking them.